Color-changing diaspore from green in daylight to brown in incandescent light - also known as “Zultanite” in the gem market.Photo courtesy of Chaman Golecha, Gem Testing Laboratory, Jaipur.

Diaspore as a plausible gemstone has been reported first around 1977 when a large enough crystal was examined at the Gem Testing Laboratory in London. This, usually colorless, material showed good color-change from pale bluish-green to pale pinkish-brown. Turkey was the origin of this color-change material.
When Zultanite Gems LLC aquired the mining location, this color-change variety of diaspore was marketed under the tradename "zultanite®". At present (2007) sole distribution rights of "zultanite®" are granted to GemsTV.